To power on the system, which of the following can be used on the MacBook Pro (Retina, Mid 2012) and MacBook Pro (Retina, 15-inch, Early 2013 and Late 2013)
logic boards?

A.
Two switches that can be flipped

B.
Two ports that be activated

C.
Two pads that can be shorted

D.
Two buttons that can be pressed